v3.19.3.a.u2

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Options Activity

The following table summarizes our option activity as of December 31, 2019 and 2018:

		Number of Options			Weighted Average Exercise Price per Share			Weighted Average Grant Date Fair Value per Share			Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value (1) (in thousands)
Outstanding at December 31, 2018		50,821,132			12.16			6.59			7.1 years		220,434
Granted		7,354,268			19.58			11.35
Exercised		(6,945,306	)		6.86			4.47
Canceled/forfeited		(5,693,179	)		15.17			8.67
Outstanding at December 31, 2019		45,536,915			13.82			7.35			7.2 years		286,310
Exercisable at December 31, 2019		22,872,221			10.13			4.86			5.9 years		216,241
Expected to vest at December 31, 2019		22,664,694			17.54			9.86			8.6 years		70,069

_______

⁽¹⁾Aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of common stock for those options in the money as of December 31, 2019.

Restricted Common Stock Activity

The following table summarizes our restricted stock activity during the year ended December 31, 2019:

	Number of Shares			Weighted Average Grant Date Price per Share
Outstanding, non-vested at December 31, 2018	198,597			$	12.15
Issued	—			—
Vested	(162,717	)		12.15
Canceled/forfeited	(35,880	)		12.15
Outstanding, non-vested at December 31, 2019	—			—

Restricted Common Stock Units Activity

The following table summarizes our restricted stock unit activity during the year ended December 31, 2019:

	Number of Units			Weighted Average Grant Date Price per Unit
Outstanding, non-vested at December 31, 2018	458,715			$	11.93
Issued	1,283,662			19.12
Vested	(57,344	)		11.93
Canceled/forfeited	(106,413	)		20.25
Vested in prior year and settled during the period	(401,371	)		11.93
Outstanding, non-vested at December 31, 2019	1,177,249			19.01

Weighted-Average Assumptions Used to Estimate the Fair Value of Options Granted

The weighted-average assumptions used to estimate the fair value of options granted and ESPP for the years ended December 31, 2019, 2018 and 2017 are as follows:

		Weighted Average
		Years Ended December 31,
		2019				2018				2017
Options:
Risk-free interest rate		2.29		%		2.76		%		2.02		%
Expected term		6.07 years				6.27 years				6.21 years
Expected volatility		61		%		63		%		63		%
Expected dividends		—		%		—		%		—		%
Weighted average fair value per share		$	11.35			$	9.33			$	7.96
ESPP:
Risk-free interest rate		1.95		%		*				*
Expected term		0.50 years				*				*
Expected volatility		53		%		*				*
Expected dividends		—		%		*				*
Weighted average fair value per share		$	5.98			*				*

_________

* - Not applicable

Stock-Based Compensation Expense

The following table presents the components and classification of stock-based compensation expense for the years ended December 31, 2019, 2018 and 2017 as follows (in thousands):

	Years Ended December 31,
	2019				2018				2017
Options	$	74,780			$	63,288			$	31,724
Restricted common stock and units	5,125				9,277				8,331
Employee stock purchase plan	1,217				—				—
Total	$	81,122			$	72,565			$	40,055
Research and development	$	48,259			$	37,659			$	21,679
General and administrative	32,863				34,906				18,376
Total	$	81,122			$	72,565			$	40,055

X

- References

No definition available.

+ Details

Name:	us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the changes in outstanding nonvested restricted stock shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of allocation of amount expensed and capitalized for award under share-based payment arrangement to statement of income or comprehensive income and statement of financial position. Includes, but is not limited to, corresponding line item in financial statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

+ Details

Name:	us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the changes in outstanding nonvested restricted stock units.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of number, weighted-average exercise price or conversion ratio, aggregate intrinsic value, and weighted-average remaining contractual term for outstanding and exercisable options that are fully vested and expected to vest. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAndExercisableTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration